Raga Cha is a transcription of an improvisation by Derek Charke. It is not based on any authentic Raga, but rather attempts to emulate the sound world through the use of various extended flute techniques. It is repetitive and meditative in character. The title ‘Cha’ is derived from the primary technique used to produce most sounds in this work, whereby the flutist must enunciate the word ‘cha’ to produce the desired effect. One of the flutes acts as the tabla, this is accomplished by singing and playing at the same time. Alteration between a low and high pitch is achieved, not by changing fingerings, or pitch, but by changes in vowel sounds and a sudden increase in air pressure, adding higher harmonics. Another flute takes on the role of drone, acting as the Surpeti (Swar peti) or Shruti Box. Two more flutes provide variations on a simple, descending, natural minor scale. Each part has its own distinctive rhythm, that taken as a whole sounds rather complex. A hemiola rhythm, 2 against 3, opens the piece. Later still 3 against 4 is introduced as the piece builds in complexity. Two thirds of the way into the piece the tonic changes from C in the dorian mode, to E-flat lydian. Further still the tonic changes to G in an aeolian mode, ultimately returning to, and ending on, the original C dorian.

"The admirable simplicity of the concept kept the audience riveted on catching the tiniest details." – Stephen Pedersen, The Chronicle Herald

Several different arrangements are possible. This list shows the combinations that have been used: